0012 Xbox 360 secondary error code | Three red rings guide
An error about heat...kind of.
This error code deals with the GPU reaching a maximum temperature. Once that temperature is reached, the console shuts down and a 0012 secondary error code is thrown on the Xbox 360 console. This may seem obvious at first, but this can be simple or difficult to diagnose and repair. Keep in mind, the Xbox 360 S models have a combined CPU and GPU under one heatsink. These tips will apply the same as the phat version just on the single chip. Time to break it down further!
Could be major
I'll go ahead and start with the worst possibility on this one. As discussed earlier, the 0012 error code is cause by the temperature. But... what if it isn't actually overheating? A thermal sensor primarily attached to the HANA/ANA computer chip can be damaged or malfunctioning. This could be the cause as well. If the sensor doesn't send info through the southbridge, your Xbox 360 will automatically assume the GPU is overheating, causing the 0012 error to populate. This means you would need to replace the sensor with a new one. (Keep reading though, there are some simple things to try first!) Additionally, damaged or broken traces will have the same effect if they directly connect to that thermal sensor. Any capacitors that are missing or blown can also cause the 0012 error. In this case, most users will not have the tools or skills to complete a repair such as this. For those of you who wouldn't be able to repair, replacing the motherboard is also a solution!
Could be minor
As stated above, there are some simple things you should try before replacing the motherboard or fixing the thermal sensor. This 0012 secondary error code might be caused by, you guessed it, actual overheating on the GPU. The Xbox 360 console used very poor quality thermal compound on the heatsinks. Removing the GPU heatsink and replacing the compound could very well solve your problem! I will add a video tutorial on how to do that below this paragraph! The heatsink itself could cause the 0012 error. It could be damaged or too loose. Replacing the GPU heatsink may also help you! They are relatively cheap, so even if you don't find damage, replacing it isn't a bad idea.
